This invention relates to an insulated glass fiber reinforced concrete/steel wall section and a method for economically and efficiently fabricating the wall sections.
The manufacture of standard glass fiber reinforced cement (GFRC)/steel stud wall sections has been standard practice for several years. The industry has generated an enormous amount of data on both their structural durability and their utility for application to commercial buildings. They have not been widely used in the residential market because of inherent design problems. The primary reasons are the cost of manufacture inherent in a predominantly skilled labor intensive, low production system for producing the wall sections and the fact that the use of currently available GFRC panels is limited to architecturally decorative applications in the residential market since the wall sections have poor insulating value.
Such wall sections have many advantages. They are rot proof, vermin proof, termite proof, carpenter ant proof, warp proof, split proof, creep proof, creak proof, crack proof, non-toxic and maybe engineered to the highest seismic ratings. Further, these wall sections do not add fuel to a fire. Such GFRC panels and methods of fabricating such panels have been described in some detail in GFRC Recommended Practice For Glass Fiber Reinforced Concrete Panels, Third Edition, published by Pre-cast/Pre-stressed Concrete Institute, 1993. This publication describes current practices for use in the production of GFRC panels and their use in the fabrication of glass fiber reinforced cement/steel stud wall sections.
As described in the above publication, these wall sections have the advantages discussed above. However, they are also subject to the disadvantages that they have very poor insulating properties and that the steel wall studs tend to xe2x80x9csweatxe2x80x9d since they become colder than the inside environment of most dwellings as a result of the high conductivity of the glass fiber reinforced concrete and the steel which are in direct thermal contact via the rods which fasten the glass fiber reinforced concrete panels to the steel wall studs. Wall sections of this type have been fabricated by producing the glass fiber reinforced concrete panels and thereafter positioning the steel wall section frame in position relative to the glass fiber reinforced concrete panels by the use of thermally conductive metal fasteners. The materials used as fasteners are generally steel rods having a diameter from about xe2x85x9c to about xc2xd inch and are suitable for welding to the steel wall studs at one end with the other end of the rod, which is desirably bent to be generally parallel to a back surface of the concrete panel, being positioned at the desired location relative to the panel and then fastened in position by positioning a bonding pad of the glass fiber reinforced concrete over the end of the rod near the panel to retain the end of the rod in position relative to the back of the panel. The wall studs must be of a thickness sufficient for welding to the rods. This technique has been effective to fasten the concrete panel and the steel wall stud frame together, but it has provided a path for conduction of heat from the concrete panel to the wall studs. Since both of these materials are conductive, these wall sections offer very little insulating value. As a result, the steel wall studs tend to sweat. Insulation can be placed inside the steel wall studs but the presence of such insulation inhibits the installation of electrical lines, plumbing lines and the like between the studs and does little to inhibit the conduction of heat when conductive metal rods are in direct contact with both the steel wall studs and the concrete panel. A direct conductive heat path to the outside of the panel is provided.
It is desirable to achieve the advantages available from steel wall stud frames in conjunction with glass fiber reinforced concrete panels to form wall sections. A continuing search has been directed to the development of an improved method for fabricating such wall sections economically and efficiently and to the development of a method, which will provide such wall sections having a higher insulation value.
According to the present invention it has been found that desirable heat transfer characteristics and desirable wall sections of glass fiber reinforced concrete and steel wall studs are achieved with an insulated glass fiber reinforced concrete/steel wall section comprising:
a) a wall section frame comprising at least two steel wall studs and at least two steel end plates;
b) a glass fiber reinforced concrete panel having a front side facing away from the wall section frame and a back side facing toward the wall section frame and having a plurality of bonding pads on its back side;
c) a plurality of straps each having a first and a second end, the first ends being insulated and positioned in the bonding pads and the second ends being connected to the wall section frame; and,
d) insulation positioned between the backside of the glass fiber reinforced panel and the wall section frame.
Such wall sections are efficiently fabricated by a method comprising:
a) producing a steel wall section frame by joining at least two steel wall studs to a top and a bottom plate to form the steel wall section frame;
b) positioning a restraining frame about the steel wall section frame;
c) positioning a formed insulation having a plurality of cavities, each having a bottom above the steel wall section and inside the restraining frame,
d) positioning a plurality of straps each having a first end and a second end, the second end having insulation over the second end with the first ends being connected to the wall studs and with the second ends being positioned in the cavities with a selected space between the second ends and the bottoms of the cavities; and,
e) filling the cavities and the frame above the formed insulation to a selected level with fluid glass fiber reinforced concrete to form a glass fiber reinforced panel.
The invention further comprises an insulated glass fiber reinforced concrete/steel wall section comprising a wall section frame comprising at least two steel wall studs and at least two steel end plates; a glass fiber reinforced concrete panel having a front side facing away from the wall studs and a back side facing the wall studs and having a plurality of bonding pads on its back side; and, a plurality of fasteners, the fasteners having a first and a second end, the first ends of the fasteners being insulated and positioned in the bonding pads and the second ends of the fasteners being connected to the wall section frame to support the panel in spaced relationship to the wall section frame with a space between the panel and the wall section frame.
The invention further comprises a method for fabricating an insulated glass fiber reinforced concrete/steel wall section by producing a steel wall section frame by joining at least two steel wall studs to a top and a bottom plate to form the steel wall section frame; connecting a plurality of fasteners, the fasteners having a first and a second end, the first ends being insulated, to support the steel wall section frame in spaced relationship to a glass fiber reinforced panel by positioning the first ends of the fasteners in supporting contact with the panel by positioning the first ends of the fasteners in bonding pads on a back surface of the panels and positioning the second ends of the fasteners in supporting contact with the wall frame.
The invention further comprises an insulated glass fiber reinforced panel for use in producing a glass reinforced concrete/steel wall section, the panel comprising a glass fiber reinforced panel having a first and a second side and a plurality of formed bonding pads on its first side; a formed insulation member having a first and a second side and a plurality of cavities containing the formed bonding pads on its first side; and a plurality of fasteners each having a first fastener end and a second fastener end, the first fastener end being insulated and positioned in a formed bonding pad with the fasteners extending from the formed bonding pads past or through the second side of the formed insulation.
A method for producing an insulated glass fiber reinforced panel for use in producing a glass reinforced concrete/steel wall section by positioning a frame about and extending above a formed insulation member having a plurality of cavities in its upper surface; positioning a plurality of fasteners, each of the fasteners having a first fastener end and a second insulated fastener end, so that an insulated fastener end is positioned in each cavity and filling the frame above the formed insulation member with fluid glass fiber reinforced concrete to form a glass fiber reinforced concrete panel above the formed insulation member.
Wall sections may be formed with the panels by attaching a steel wall section frame to the panel by attaching the second fastener ends to the steel wall section frame.